1. Field of the Invention
The present invention relates to thermal transfer receivers adapted to form transferred images with excellent solvent resistance and superior wear resistance, methods for producing the same, methods for recording images, and recorded images.
2. Description of the Related Art
Methods for forming images through heating a thermal transfer medium by use of a thermal head and a transferring ink onto a receiving medium are publicly known and are broadly utilized for making labels such as nameplates. When such labels are utilized under circumstances containing organic solvents such as methylethylketone (hereinafter referring sometimes as “MEK”), the images transferred on the labels should be free from erasing under the effect of solvents.
In Japanese Patent Application Laid-Open (JP-A) No. 04-115995, JP-A No. 05-286227, JP-A No. 08-43994, and JP-A No. 08-58250, receivers are disclosed that contain ethylene-ionomer resins in the receiving layer in order to improve ink-transferability and chemical resistance of the receivers. A receiver is proposed in JP-A No. 2002-113959 that comprises a coating layer composed of ethyleneimine additives made from olefin-unsaturated carboxylic acid copolymers and polyimine polymer. However, the solvent resistance is insufficient in these proposals with respect to images formed on the receiving layer and the coating layer.
Further, in order to obtain the adequate solvent resistance of transferred images, same kind of resins superior in solvent resistance are added to the ink layer and the receiving layer. For example, in Japanese Patent (JP-B) No. 2533456, adding a specific polyolefin to the ink resin and the receiving layer is proposed. Also, in JP-A No. 04-347688 and JP-A No. 2001-199171, adding nylon to the ink layer and the receiving layer is proposed. However, these proposals suffer from insufficient solvent resistance of the images for sever applications.
Further, an under layer is provided between the receiving layer and the support in order to strengthen the receiving layer and thus to increase the wear resistance in receivers containing a receiving layer. Specifically, an under layer containing a UV cure resin is provided between the receiving layer and support (e.g. JP-A Nos. 61-112693, 61-121993, 01-228890, 01-244890, 02-223495, and 04-275194). However, these proposals suffer from the insufficient strength of the receiving layer, in particular the lower solvent resistance of images on the receiving layer.